Abstract Papers:

اين مقاله روشي جديد در تشخيص پايداري گذرا به نام روش تركيبي پايداري گذرا يا CTS ارائه مي‏كند. در اين روش هم از روش شبيه‏سازي و هم از روش PEBS اتاي بهره گرفته شده است. به همين دليل اين روش، روش تركيبي پايداري گذرا ناميده شده است. CTS از تمام روشهايي كه بدنبال نقطه تعادل ناپايدار كنترل‏كننده مي‏باشند داراي قابليت اطمينان بيشتري مي‏باشد. رسيدن به جواب به دليل عدم استفاده از روشهاي همگرايي حتمي است و به تغييرات بار و نقاط مار سيستم وابستگي چنداني ندارد. با آزمايش بر روي سيستمي داراي 4 ماشين و 7 باس كه نتايج آن در آخر مقاله آورده شده است بطور عملي و از نظر تئوري برتري اين روش نسبت به PEBS اثبات شده است.

در اين مقاله يك كنترل كننده PID فازي براي يك ربات با بار متغير با زمان با استفاده از نرم‏افزار فازي طراحي شده است. ابتدا كنترل كننده PID فازي توضيح داده شده مي‏شود كه ساختار اين كنترل كننده خطي بوده ولي گينهاي تناسب، مشتق و انتگرال بصورت توابعي غيرخطي از ورودي مي‏باشند بطوريكه كاملاً با ورودي مطابقت دارند به عبارت ديگر، اين گينهاي متغير، باعث سرعت بيشتر كنترل كننده و جهش كمتر نسبت به حالت غير فازي مي‏شوند. در اين مقاله بطور مؤثري از نرم‏افزار فازي مطلب تحت ويندوز استفاده شده كه كارآيي و سرعت طراحي را بسيار بالا برده است. نتايج اين تحقيق در آخر مقاله آورده شده است.

هر سيستم ديناميكي كه طراحي و يا ساخته مي‏شود بايد در شرايط پايدار كار كند. در اين شرايط بايد بصورت رضايت بخشي به كار خود ادامه دهد و با يك حاشيه ايمني مناسب بتواند در تمام زمانها حتي در زمان وقوع خطا، پايدار بماند. هنگاميكه يك سيستم ديناميكي مانند يك سيستم قدرت به هم پيوسته با خطوط انتقال طولاني، بزرگ و پيچيده باشد بررسي پايداري با استفاده از يك روش تحليل و عملي بسيار مؤثر خواهد بود. روش مستقيم يا روش دوم لياپانوف، بدون حل معادلات ديفرانسيل سيستم، بيان مي‏كند كه بعد از هر اغتشاش چگونه سيستم به حالت پايدار باز مي‏گردد. جاذبه اين روش در توانايي محاسبه مستقيم زمان قطع بحراني در ازاي خطاهاي مختلف مي‏باشد. همچنين درجه پايداري سيستم در حال كار را مشخص مي‏كند. در كاربردهاي غير همزمان نيز باعث افزايش سرعت و اطمينان محاسبه زمان قطع بحراني مي‏شود. اين روش را مي‏توان به عنوان مكمل روش شبيه‏سازي نيز بكار برد.

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در اين مقاله تاثير SMES بر پايداري گذراي ژنراتور سنكرون و بهبود نوسانات LFC در سيستم قدرت دو منطقه‏اي بطور جداگانه مورد مطالعه قرار گرفته است. همچنين SMES به اختصار معرفي شده و تاثير آن بر كنترل بار- فركانس بررسي شده است. در اين قسمت ضمن محاسبه مقدار بهينه بهره انتگراتور در حلقه ALFC، نشان داده شده است كه SMES نه تنها بطور مؤثري ميرايي نوسانات سيستم را بهبود بخشيده، بلكه بطور كلي، كاربرد آن كاهش حساسيت نسبت به تغيير پارامترها را نيز بدنبال داشته است. در قسمت آخر، تحليل پايداري گذراي يك ژنراتور سنكرون متصل به پين بي‏نهايت بررسي شده است.

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روش تابع انرژي كاربرد زيادي در تشخيص پايداري گذراي سيستم قدرت پيدا كرده است. به دليل پيشرفت زيادي كه در تعيين توابع مختلف انرژي و روشهاي مستقيم ابداع شده است اين روش قدرت زيادي براي تعيين پايداري ولتاژ دارد. در اين مقاله معيار جديدي براي تعيين فروپاشي ولتاژ با استفاده از روش تابع انرژي ارائه شده است.

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در اين مقاله از يك روش جديد در تشخيص پايداري گذرا استفاده شده و از روش PEBS اتاي بهره گرفته شده است. روش POMP بدنبال نقطه ماكزيمم انرژي پتانسيل بر روي مسير سيستم بعد از خطا مي‏باشد كه اين نقطه با بسط تيلور مرتبه دوم تقريب زده شده است. با استفاده از اين نقطه در الگوريتم اتاي، سرعت و دقت اين روش بالا رفته است. اين روش از تمام روشهايي كه بدنبال نقطه تعادل ناپايدار كنترل‏كننده مي‏باشند داراي قابليت اطمينان بيشتري مي‏باشد. رسيدن به جواب به دليل عدم استفاده از روشهاي همگرايي حتمي است و به تغييرات بار و نقاط مار سيستم وابستگي چنداني ندارد. با آزمايش بر روي سيستمي داراي 4 ماشين و 7 باس كه نتايج آن در آخر مقاله آورده شده است بطور عملي و از نظر تئوري برتري اين روش نسبت به PEBS اثبات شده است.

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در اين مقاله بر اساس اطلاعات بار براي هر دو شبكه خراسان و سيستان- بلوچستان در طول يك سال و همچنين، ظرفيت و نرخ خروج اجباري ژنراتورها، حداقل ظرفيت خط اتصالي بين دو شبكه بگونه‏اي محاسبه مي‏شود كه تغييرات احتمال خطاي شبكه خراسان كم شده و ميزان قابليت اطمينان شبكه بهم پيوسته بيشينه گردد. سپس از بين چند خطي كه بطور تجربي براي اتصال دو شبكه پيشنهاد مي‏شوند خطوط اضافي به روش شاخص اثرگذار حذف مي‏شوند تا شبكه‏اي بهينه از نظر اقتصادي و كارآيي حاصل شود.

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در اين مقاله حساسيت پايداري سيستم قدرت، وقتي تغييراتي در پارامترهاي آن (مقدار توليد يا ساختار شبكه) اتفاق مي‏افتد بطور تحليل ارزيابي مي‏شود. همچنين روش حساسيت خيلي سريع، براي تغييرات بوجود آمده در شبكه، ارائه شده است و اين نتايج با روشهاي دقيق مقايسه شده است. سرعت و دقت اين روش اين روش در يك مثال و در آخر مقاله نشان داده شده است.

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This paper is organized as follows: First, mathematical formulate for decomposition of power flows are derived assuming a single slack bus. Next, the concept of distributed slack bus is introduced to account for the fact that many generators are participating in ED (Economic Dispatch) generation when balancing the power on the systems. The derived decomposition formulae are generalized to account for the ramification of distributed slack bus on our proposed approach. Using the derived decomposition formulae, the power imbalance at the ED generating units is calculated.

Abstract: This paper proposes two new approaches for transient stability analysis and they have the new ideas. These approaches use Athay's PEBS [1]. The first method is called CTSA that it's complex simulation and Athay's PEBS. CTSA is more reliable than all existing methods that use unstable equilibrium point (UEP) as it doesn't use any convergence methods [2,3]. POMP's method follows the point of maximum potential energy on post-fault system trajectory that this point is approximated to Taylor's expansion second orders. This paper presents a detailed implementation of a fast and accurate method for Available Transfer Capability (ATC) calculations. We use two new methods for termination criteria in ATC calculations.

A novel formulation of the ATC problem has been adopted based on full ac power flow solution with matrix operations to incorporate the effects of voltage limits, and voltage collapse. This program written by MATLAB and don't use any do loop, then this power flow program is fivefold faster than any program in MATLAB.

The ideas are demonstrated on 4, 7 and 30 bus IEEE.

In this paper a method for tie line planning is suggested in which the identities of the individual systems in an interconnected group are retained and reliability analysis is performed for each system separately, so that contractual limitations in the assistance given to each other can be accounted for and the several characteristics of the tie lines between the systems such as their load carrying capacity and their unavailability can also be considered. The loads in the various systems may be independent or completely correlated. We assume a two region interconnected system, both identical to IEEE RTS connected by a tie line. In this paper we show how the reliability of system A in improved after it has been supported by system B and the effect of tie capacity on the failure probability is quite pronounced up to certain tie capacity. This can form the basis optimal tie line planning.

In this paper a method for tie line planning is suggested in which the identities of the individual systems in an interconnected group are retained and reliability analysis is performed for each system separately, so that contractual limitations in the assistance given to each other can be accounted for and the several characteristics of the tie lines between the systems such as their load carrying capacity and their unavailability can also be considered. The loads in the various systems may be independent or completely correlated. We assume a two region interconnected system, both identical to IEEE RTS connected by a tie line. In this paper we show how the reliability of system A in improved after it has been supported by system B and the effect of tie capacity on the failure probability is quite pronounced up to certain tie capacity. This can form the basis optimal tie line planning.

Abstract—Order 889 mandated each control area to compute ATC (Available Transfer Capability) and post them on a communication system called the Open Access Same-Time Information System (OASIS). Approaches of computing ATC can be divided into the following groups: static methods and dynamic methods. This paper presents a new dynamic method for FCTTC calculations with transient stability (TS) and voltage stability (VS) termination criteria. We present a method for TS and VS assessment simultaneously. A novel formulation of the ATC problem has been adopted based on full ac power flow solution with matrix operations to incorporate the effects of voltage limits, and voltage collapse. This program written by MATLAB and don't use any do loop, then this load flow (LF) program is fivefold faster than any LF program in MATLAB. The ideas are demonstrated on 4, 7 (CIGREE) and 30 bus IEEE and a 145 bus (Iowa State University).

Approaches of computing ATC (Available Transfer Capability) can be divided into the following groups: static and dynamic methods [1]. This paper presents a fast dynamic method for ATC calculations with transient and voltage stability (TSA and VSA) termination criteria. We use estimate of the determinant of Jacobian matrix for assessment of voltage stability [2]. This method is compared with these methods: difference between energy in SEP (Stable Equilibrium Point) and UEP (Unstable Equilibrium Point) [3-8], ts index of Dr. Chiang [9] and continuation power flow [10,11]. TSA method use Athay’s PEBS (Potential Energy Boundary Surface) [12] and a new method (POMP). POMP’s method [13,14] follows the Point Of Maximum Potential (POMP) energy on post-fault system trajectory that this point is approximated to Taylor’s expansion second order. This method is more reliable than all existing methods that use unstable equilibrium point, as it doesn’t use any convergence methods. The goals of new algorithm are assessment of ATC with VSA and TSA simultaneously, assessment of dangerous contingency and approximate of SEP trajectory for changing power. The ideas are demonstrated on 2, 3, 7 (CIGREE), 10, 30 (IEEE) and 145 bus (Iowa State University).

This paper proposes two approaches for transient and voltage stability analysis (TSA and VSA). TSA methods use Athay’s PEBS (Potential Energy Boundary Surface). The first method is called CTSA (Complex TSA) that it’s complex simulation and Athay’s PEBS. POMP’s method follows the Point Of Maximum Potential (POMP) energy on post-fault system trajectory that this point is approximated to Taylor’s expansion second order. These methods are more reliable than all existing methods that use unstable equilibrium point (UEP), as it doesn’t use any convergence methods. We use estimate of the determinant of Jacobian matrix for VSA. This method is compared with these methods: difference between energy in SEP (Stable Equilibrium Point) and UEP, ts index of Dr. Chiang and continuation power flow. The approach proposed here for VSA and TSA simultaneously is to convert the DAE (Differential-Algebraic Equation) problem (local dynamics and algebraic constraints) to an ODE (Ordinary Differential Equation) problem by differentiation the network constraints. Also, using POMP we determine whether post-fault trajectory is reached the domain of attraction for TSA (by PEBS) first or domain of attraction for VSA (by estimate of determinant). The ideas are demonstrated on 2, 3, 7 (CIGREE), 10, 30 (IEEE) and 145 bus (Iowa State University).

This paper proposes two approaches for transient stability analysis and they have the new ideas. These approaches use Athay's PEBS. The first method is called CTSA that it's complex simulation and Athay's PEBS. CTSA is more reliable than all existing methods that use unstable equilibrium point (UEP), as it doesn't use any convergence methods. POMP's method follows the point of maximum potential energy on post-fault system trajectory that this point is approximated to Taylor's expansion second orders. This paper presents a detailed implementation of a fast and accurate method for Available Transfer Capability (ATC) calculations. We use two new methods for termination criteria in ATC calculations. A novel formulation of the ATC problem has been adopted based on full ac power flow solution with matrix operations to incorporate the effects of voltage limits, and voltage collapse. This program written by MATLAB and don't use any do loop, then this power flow program is five times faster than any program in MATLAB. The ideas are demonstrated on 4, 7 and 30 bus IEEE.

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Order 889 mandated each control area to compute ATC (Available Transfer Capability) and post them on a communication system called the Open Access Same-Time Information System (OASIS). Approaches of computing ATC can be divided into the following groups: static methods and dynamic methods. This paper presents a new dynamic method for FCTTC calculations with transient stability (TS) and voltage stability (VS) termination criteria. We present a method for TS and VS assessment simultaneously. A novel formulation of the ATC problem has been adopted based on full ac power flow solution with matrix operations to incorporate the effects of voltage limits, and voltage collapse. This program written by MATLAB and don't use any do loop, then this load flow (LF) program is five times faster than any LF program in MATLAB. The ideas are demonstrated on 4, 7 (CIGREE) and 30 bus IEEE and a 145 bus (Iowa State University).

This paper presents a fast dynamic method for ATC calculations with considering transient stability analysis (TSA) and voltage stability analysis (VSA) termination criteria. This method can be used for contingency screening and ranking. Estimation of the determinant of Jacobian matrix is used for assessment of voltage stability. This method is compared with the following methods: energy difference between SEP (Stable Equilibrium Point) and UEP (Unstable Equilibrium Point), t_s index of Chiang, and continuation power flow. TSA method use Athay’s PEBS (Potential Energy Boundary Surface) and a new method named POMP. The POMP method follows the Point Of Maximum Potential (POMP) energy on post-fault system trajectory. This point is approximated by Taylor’s expansion of second order. Since this method doesn’t use any convergent algorithm, it is more reliable than all existing methods that use UEP. The goals of this method are assessment of ATC with considering VSA and TSA simultaneously and assessment of dangerous contingencies. The ideas are demonstrated on 2, 3, 7 (Cigre), 10, 30 (IEEE) and 145 (Iowa State) bus networks.